5§4 
Notes  on  Insect  Powder. 
Am.  Jour.  Pharoi. 
Dec,  1891. 
amount  and  constituents  of  ash,  and  behavior  of  the  chloroform 
extract  towards  reagents,  were  the  essential  tests  taken  up,  the  prac- 
tical "  insecticide  "  test,  as  applied  to  flies  and  cockroaches,  being 
omitted  for  want  of  time  and  insects. 
The  color  of  the  samples  coincided  with  the  chemical  examination, 
samples  one  to  five  being  quite  alike  in  color,  while  number  six  was 
of  a  deep  yellow  and  number  seven  less  so. 
The  dealer  in  buying  should  insist  upon  securing  a  fawn  or  light 
yellowish  brown  colored  powder  and  look  with  suspicion  upon  the 
deep  and  bright  yellow  ones. 
The  ash  of  a  genuine  insect  powder  should  not  run  over  eight  per 
cent.  Anything  above  this  should  be  examined  carefully  for  some 
lead  or  barium  salt.  The  ash  should  be  almost  entirely  soluble  in 
hydrochloric  acid,  but  if  part  is  insoluble  and  the  clear  fluid  becomes 
green  upon  boiling,  H2S  produces  a  black  precipitate  and  KI  a  bright 
yellow  crystalline  one,  it  may  be  accepted  as  conclusive  proof  that 
lead  chromate  is  present. 
Recapitulation  of  analyses : 
Chloroform  Extract 
Name. 
Color. 
%  Ash. 
Constitu- 
ents of  ash. 
Color. 
and  Bora- 
cic  acid 
for  Tur- 
meric. 
and  Hydro- 
chloric 
Acid. 
Adultera- 
tion. 
Microscop- 
ical Exami- 
nation. 
Dalmatian, 
Fawn. 
6-5 
Normal. 
Greenish 
brown. 
Negative. 
Slightly 
green. 
None. 
No  foreign 
starches. 
Dalmatian 
(uncolored) 
Yellowish 
brown. 
6-6 
Normal. 
Yellowish 
brown. 
Negative. 
Greenish. 
None. 
No  foreign 
starches. 
Dalmatian 
(extra), 
Light 
yellowish 
brown. 
6'9 
Normal. 
Yellowish 
green. 
Negative. 
Slightly 
green. 
None. 
No  foreign 
starches. 
Dalmatian, 
I,ightfawn. 
6'59 
Normal. 
Brownish 
green. 
Negative. 
Greenish. 
None. 
No  foreign 
starches. 
Dalmatian, 
Light 
yellowish 
brown. 
6-a 
Normal. 
Greenish. 
Negative. 
Deep 
green. 
None. 
No  foreign 
starches. 
True  insect 
powder, 
Deep 
yellow. 
12-6 
Normal 
and  lead 
chromate. 
Pale 
yellow. 
Negative. 
Slightly 
green. 
Chrome 
yellow 
about  6  <$>. 
No  foreign 
starches. 
Dalmatian, 
Dark 
yellow. 
26-8 
Normal 
and  lead 
chromate. 
Greenish. 
Negative. 
Distinctly 
green. 
Chrome 
yellow 
about  20  <fo. 
No  foreign 
starches. 
Parke,  Davis  &  Co.,  Analytical  Laboratory,  Nov.  6, 1891. 
